Evidence-based·Last reviewed May 31, 2026·How we grade evidence

Linolenic Acids

Q: Are alpha-linolenic and gamma-linolenic the same?

No. Despite similar names, ALA is omega-3 (from flax, chia, walnuts) and GLA is omega-6 (from borage, evening primrose). They have different metabolic roles.

Q: Can I rely on ALA instead of fish oil?

Only partially. Most people convert only 5-15% of ALA to EPA and less than 1% to DHA. If you want robust omega-3 effects, EPA/DHA from fish oil or algae oil are more reliable.

Q: Is GLA worth taking for joint pain?

For rheumatoid arthritis, moderate evidence supports GLA at 1.4+ g/day. For general joint pain, evidence is weaker; other interventions may be more effective.

Q: How much ALA do I need?

Adequate Intake is 1.1 g/day for women and 1.6 g/day for men. One tablespoon of ground flaxseed provides roughly 2.4 g.

Fatty-acidBest with a meal

'Linolenic acids' is a class label covering α-linolenic acid (ALA, an essential omega-3 found in flax, chia, walnuts) and γ-linolenic acid (GLA, an omega-6 found in evening primrose, borage, blackcurrant seed). The two have different uses: ALA is part of cardiovascular risk reduction (Pan 2012 meta-analysis: each 1 g/day → 10% lower CHD death), while GLA shows modest benefit for rheumatoid arthritis pain (Cochrane 2011) and no clinical benefit for atopic eczema (Cochrane 2013). Most people get ALA from food; GLA is only worth supplementing for specific conditions.

Quick decision guide

May help most

ALA: anyone wanting plant omega-3 (vegetarians/vegans, people who don't eat seafood). GLA: adults with rheumatoid arthritis seeking a low-risk adjunct.

Common dosing range

ALA: 1.1–1.6 g/day from food (a tablespoon of ground flaxseed + a handful of walnuts covers this). GLA: 1–3 g/day for RA, typically from borage oil (≈200–500 mg GLA/day at 20–25% concentration).

When to expect effects

ALA cardiovascular signal accrues over years. GLA RA pain reduction takes 8–12 weeks in trials.

Watch out for

ALA conversion to EPA/DHA is limited (~5–10%). If you specifically want EPA/DHA benefits (triglyceride lowering, mood), use fish oil or algal oil — not ALA. For GLA, borage products must be UPA-free (pyrrolizidine alkaloid hepatotoxicity).

Evidence snapshot

ALA: cardiovascular (CHD death)Moderate

ALA: EPA/DHA conversionLimited

GLA: rheumatoid arthritis painEmerging

GLA: atopic eczemaNot effective

What is it

Linolenic acids are a family of polyunsaturated fatty acids including alpha-linolenic acid (ALA, omega-3, found in flax and chia), gamma-linolenic acid (GLA, omega-6, found in evening primrose and borage oil), and stearidonic acid (SDA, omega-3). Each has distinct biological roles despite similar names.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You eat little or no seafood and want plant-based omega-3 (ALA) for cardiovascular health — flax, chia, walnuts cover it

You have rheumatoid arthritis and want to add a low-risk GLA-containing oil to standard care (typically 1.4–2.8 g/day GLA from borage)

You're rebuilding diet quality and want to replace omega-6-heavy refined oils with ALA-rich whole foods

You're a vegetarian/vegan considering algal EPA/DHA — ALA alone isn't enough; consider an algal-DHA supplement

Probably skip if…

You eat 2+ servings/week of fatty fish — you're already getting EPA/DHA, which is more efficient than relying on ALA conversion

You're using GLA (evening primrose oil) for atopic eczema — Cochrane 2013 found no clinically meaningful benefit vs placebo

You're taking high-dose borage oil without a UPA-free certification — uncertified products can contain hepatotoxic pyrrolizidine alkaloids

You're hoping plant ALA will substitute for fish oil for triglyceride lowering or mood — EPA/DHA do those jobs; ALA's conversion is too inefficient

You're pregnant and considering borage oil — UPAs are teratogenic; use safer GLA sources or skip it

Evidence at a glance

Goal	Effect	Best fit	Time
ALA conversion to EPA and DHA Strong Evidence	ALA→EPA ~5–10%; ALA→DHA <1% in healthy adults	Vegetarians/vegans should add algal DHA supplementation rather than trying to over-eat ALA	Steady-state conversion within weeks
ALA for cardiovascular disease prevention Good Evidence	≈10% lower CHD death risk per 1 g/day dietary ALA increment (Pan 2012 meta-analysis)	Adults eating little seafood, vegetarians/vegans wanting plant omega-3 for cardiovascular risk reduction	Years (cardiovascular endpoint timescale)
GLA for rheumatoid arthritis pain Good Evidence	Pain reduction ~30 points on 100-point scale; disability reduction ~16% over 6 months in pooled RA trials	Adults with rheumatoid arthritis wanting to add a low-risk dietary adjunct to DMARD or biologic therapy	8–12 weeks for symptom improvement; full effect by 6 months
GLA for atopic eczema / dermatitis Mixed Evidence	No clinically meaningful improvement vs placebo in pooled Cochrane analysis	None — evidence does not support routine use for eczema	Not established to be effective

ALA conversion to EPA and DHA

Strong Evidence

Effect: ALA→EPA ~5–10%; ALA→DHA <1% in healthy adults
Best fit: Vegetarians/vegans should add algal DHA supplementation rather than trying to over-eat ALA
Time: Steady-state conversion within weeks

ALA for cardiovascular disease prevention

Good Evidence

Effect: ≈10% lower CHD death risk per 1 g/day dietary ALA increment (Pan 2012 meta-analysis)
Best fit: Adults eating little seafood, vegetarians/vegans wanting plant omega-3 for cardiovascular risk reduction
Time: Years (cardiovascular endpoint timescale)

GLA for rheumatoid arthritis pain

Good Evidence

Effect: Pain reduction ~30 points on 100-point scale; disability reduction ~16% over 6 months in pooled RA trials
Best fit: Adults with rheumatoid arthritis wanting to add a low-risk dietary adjunct to DMARD or biologic therapy
Time: 8–12 weeks for symptom improvement; full effect by 6 months

GLA for atopic eczema / dermatitis

Mixed Evidence

Effect: No clinically meaningful improvement vs placebo in pooled Cochrane analysis
Best fit: None — evidence does not support routine use for eczema
Time: Not established to be effective

Evidence for 4 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

ALA conversion to EPA and DHA

Mechanism only

Strong Evidence

This is a safety/expectations claim rather than a benefit: ALA conversion to EPA is limited (~5–10% in healthy adults) and to DHA is very limited (<1%). Women have somewhat higher conversion rates than men, attributed to estrogen effects on elongase/desaturase enzymes. If you want the EPA/DHA-specific effects (triglyceride lowering, mood, vision, brain development), don't rely on ALA alone — use fish oil or algal oil.

Effect size

ALA→EPA ~5–10%; ALA→DHA <1% in healthy adults

Time to effect

Steady-state conversion within weeks

Best fit

Vegetarians/vegans should add algal DHA supplementation rather than trying to over-eat ALA

Less likely

Anyone hoping flaxseed alone will meet EPA/DHA requirements — biology limits this

Bottom line: ALA is essential and worth eating, but it's not a substitute for EPA/DHA. Plant-only diets benefit from algal DHA.

SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet

ALA for cardiovascular disease prevention

Supplement benefit

Good Evidence

The Pan 2012 AJCN meta-analysis (27 studies, ~251,000 participants, ~15,300 CVD events) found each 1 g/day increment in ALA intake was associated with ~10% lower risk of fatal CHD (RR 0.90, 95% CI 0.81–0.99). The overall ALA→CVD signal is modest but consistent across observational and small interventional studies. ALA acts as both a direct cardioprotective omega-3 and (to a limited extent) as a precursor to EPA.

Effect size

≈10% lower CHD death risk per 1 g/day dietary ALA increment (Pan 2012 meta-analysis)

Time to effect

Years (cardiovascular endpoint timescale)

Best fit

Adults eating little seafood, vegetarians/vegans wanting plant omega-3 for cardiovascular risk reduction

Less likely

Adults already eating 2+ servings/week fatty fish — additional ALA gives diminishing returns

Bottom line: Meaningful and achievable from food (1 tbsp ground flax + small handful walnuts ≈ 3 g ALA). Skip the capsule; eat the seeds.

SourcePan et al., 2012 — American Journal of Clinical Nutrition NIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet

GLA for rheumatoid arthritis pain

Disease adjunct

Good Evidence

The Cameron 2011 Cochrane review found moderate evidence that GLA-containing oils (evening primrose, borage, blackcurrant seed) reduce pain (mean difference −32.83 on 100-point pain scale; 7 studies) and disability (MD −15.75%) in rheumatoid arthritis. Most trials used 1.4–2.8 g GLA/day for 6 months. The effect is real but modest, and GLA is an adjunct — not a replacement — for DMARDs or biologics. Borage oil delivers more GLA per gram (~20–25%) than evening primrose (~9%).

Effect size

Pain reduction ~30 points on 100-point scale; disability reduction ~16% over 6 months in pooled RA trials

Time to effect

8–12 weeks for symptom improvement; full effect by 6 months

Best fit

Adults with rheumatoid arthritis wanting to add a low-risk dietary adjunct to DMARD or biologic therapy

Less likely

RA patients hoping GLA will replace standard medications — it doesn't

Bottom line: Reasonable adjunct for RA. Choose UPA-certified borage oil to minimize pyrrolizidine-alkaloid risk.

SourceCameron, Gagnier, Chrubasik 2011 — Cochrane Database of Systematic Reviews Memorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine

GLA for atopic eczema / dermatitis

Supplement benefit

Mixed Evidence

The Bamford 2013 Cochrane review of evening primrose oil and borage oil for atopic eczema (19 trials, 596 EPO and 140 borage participants) concluded that neither offers clinically meaningful benefit over placebo. Earlier industry-funded trials had suggested benefit, but later well-blinded trials and the pooled analysis do not support routine use.

Effect size

No clinically meaningful improvement vs placebo in pooled Cochrane analysis

Time to effect

Not established to be effective

Best fit

None — evidence does not support routine use for eczema

Less likely

Adults with eczema hoping to avoid topical steroids — emollients, topical steroids, and modern topicals (calcineurin inhibitors, JAK inhibitors) all have better evidence

Bottom line: Don't take GLA for eczema. Use proven topicals and talk to a dermatologist about prescription options.

SourceBamford et al., 2013 — Cochrane Database of Systematic Reviews — atopic eczema

How it works

Alpha-linolenic acid (ALA) is an essential omega-3 fatty acid the body cannot make; it must come from diet. Once consumed, ALA can be partially converted (poorly, at 5-15% in most adults) to EPA and DHA, the longer-chain omega-3s with stronger anti-inflammatory and brain-supportive effects. ALA itself supports membrane structure and has weak direct effects. Gamma-linolenic acid (GLA) is an omega-6 fatty acid the body produces from dietary linoleic acid via the delta-6-desaturase enzyme. Some people convert poorly due to genetics, age, or nutrient deficiencies (B6, magnesium, zinc), making dietary GLA potentially useful. GLA can be converted to prostaglandin E1, which has anti-inflammatory effects. Different linolenic acids serve different purposes. ALA for omega-3 status when fish isn't an option; GLA for inflammatory conditions like rheumatoid arthritis or eczema.

How to take it

1. Typical dose

• ALA: target 1.1 g/day (women) or 1.6 g/day (men) from food — 1 tbsp ground flaxseed (~2.4 g), 1 oz walnuts (~2.6 g), 1 tbsp chia seeds (~2.5 g), or 1 tbsp canola oil (~1.3 g) each cover it • GLA (for RA): 1.4–2.8 g/day total GLA, typically from borage oil (look for UPA-free certification) at ~200–500 mg GLA per capsule • Don't substitute ALA for EPA/DHA — biology limits the conversion

2. Higher studied dose

ALA: Cardiovascular trials studied 2–6 g/day with diminishing returns; AHA recommends getting it from food. GLA: RA trials used up to 2.8 g/day; higher doses don't add benefit and may raise side-effect risk.

3. Timing

ALA: any time, with meals to aid absorption (n-3s are fat-soluble). GLA: with meals to reduce GI upset.

4. With food

With food.

5. Split dosing

ALA: as part of meals. GLA: split daily dose into 2–3 portions with meals.

6. How long to try

ALA: indefinite as part of a heart-healthy diet. GLA for RA: 8–12 weeks minimum to assess effect; continue if symptom benefit and rheumatologist agrees.

What to track

ALA from food: log flaxseed/walnut/chia servings until you hit the AI consistently

RA symptom diary (pain, morning stiffness, tender joint count) before and at 8/12 weeks of GLA

Side effects: GI upset, loose stools (both ALA-heavy seeds and GLA oils)

Liver enzymes if using borage oil without UPA certification (and ideally choose a certified product to skip this concern)

Bleeding tendency on anticoagulants — both n-3 and n-6 PUFAs at high doses mildly affect platelet function

Bottom line: Get ALA from food (flax, chia, walnuts, canola). Use GLA only for specific conditions (RA), choose UPA-certified borage oil, and reassess at 12 weeks.

8 commercial forms

Compare the main delivery options and what they’re best suited for.

Flaxseed (ground)

Best ALA source

Ground flaxseed (linseed) is ~58% ALA by weight. 1 tablespoon ground provides ~2.4 g ALA — more than the daily AI in one serving. Grind fresh or refrigerate to prevent oxidation. Whole seeds pass undigested.

Ground form is essential; whole seeds pass through largely intact.

Chia seeds

Convenient

Chia is ~17–20% ALA by weight; whole or ground both work (the seed coat is digestible). 1 tablespoon provides ~2.5 g ALA + ~5 g fiber. Good travel option that doesn't oxidize as fast as flaxseed.

More stable than flaxseed; whole or ground equally well-absorbed.

Walnuts

Whole-food snack

1 oz walnuts (~14 halves) provides ~2.6 g ALA. Easy snack form with whole-food nutrient package (protein, fiber, polyphenols).

Excellent — fat matrix supports absorption naturally.

Flaxseed oil (capsule or bottled)

Concentrated

Concentrated ALA (~55% by weight); 1 tsp ≈ 2.5 g ALA. Highly oxidation-prone — refrigerate; replace within 2 months of opening.

Same ALA, no fiber; check freshness — rancidity is common.

Borage seed oil (UPA-free certified)

GLA-rich

~20–25% GLA — the most concentrated dietary GLA source. Used in RA trials at 1.4–2.8 g GLA/day. Always choose a certified UPA-free product.

Higher GLA per capsule than evening primrose; UPA certification is essential.

Evening primrose oil

GLA (lower potency)

~9% GLA by weight. Larger doses needed than borage to match GLA intake. Better-known consumer product; same modest RA evidence and no eczema benefit.

Generally well-tolerated; many capsules needed to reach RA-trial GLA doses.

Blackcurrant seed oil

GLA + ALA hybrid

~15–17% GLA plus ~12–14% ALA — a hybrid source. Included in Cochrane GLA RA evidence; less commercially common than borage or evening primrose.

Mixed n-3 + n-6 polyunsaturate; well-tolerated.

Algal oil (EPA/DHA)

Beyond ALA

Microalgal source of EPA and DHA directly — bypasses ALA conversion limits. Preferred plant-based option for people who don't eat seafood. See the omega-3 / DHA pages for details.

Direct EPA/DHA; no conversion needed.

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

mild GI upset / belchingloose stools at high seed or oil intakessoft stools from ground flax (laxative effect)increased bleeding tendency at high PUFA doses (rare at typical doses)

Serious risks

Pyrrolizidine alkaloid hepatotoxicity (borage oil specifically) — uncertified borage products can contain UPAs that cause veno-occlusive liver disease with chronic use. Always choose certified UPA-free borage oil (<1 µg UPAs/day).
SourceMemorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine
Theoretical mild antiplatelet effect at high PUFA intakes (>3 g/day combined n-3 + n-6). Clinically relevant only at high doses or with concurrent anticoagulants.
SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet
Flaxseed prostate cancer signal — older small trials raised a question about high-dose ALA and prostate cancer risk. Subsequent larger meta-analyses have not confirmed a meaningful risk, but data are inconsistent.
SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet

Who should avoid it

Pregnant or breastfeeding women considering borage oil — pyrrolizidine alkaloids (in uncertified products) are teratogenic and hepatotoxic. ALA from food is safe; evening primrose oil should be discussed with an obstetrician before labor (some guides advise against use late in pregnancy due to uterine stimulation reports).
SourceMemorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine
People with seizure disorders considering evening primrose oil — some case reports suggest GLA may lower seizure threshold; discuss with neurologist before use.
SourceMemorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine
People on warfarin or other anticoagulants at high PUFA doses — discuss with prescriber and monitor INR.
SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet

Pregnancy & breastfeeding

ALA from food (flax, chia, walnuts, canola oil) is safe and beneficial in pregnancy. Evening primrose and borage oils should be used cautiously: borage oil only if certified UPA-free; evening primrose oil is sometimes used at term to soften the cervix but data are mixed and some obstetricians advise against it. Plant ALA does not substitute for the algal-DHA supplementation recommended in pregnancy/lactation.

SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet Memorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine

Bottom line: ALA from food is broadly safe and worth eating. GLA is a low-risk adjunct for RA when the source is certified UPA-free; skip it for eczema.

Interactions

warfarin and other anticoagulantsModerate

High PUFA intakes (combined n-3 + n-6 above 3 g/day) can mildly extend bleeding time. Clinically relevant mainly at high doses; monitor INR if combining.

SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet

antiplatelet drugs (aspirin, clopidogrel)Moderate

Additive mild antiplatelet effect at high doses. Use standard antiplatelet doses; don't replace them with PUFA supplements.

SourceNIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet

hepatotoxic medicationsModerate

Uncertified borage oil with UPAs adds to cumulative liver stress. Always choose UPA-free borage products if combining.

SourceMemorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine

phenothiazines and other seizure-threshold-lowering drugsMinor

Evening primrose oil case reports suggest possible lowering of seizure threshold; relevant mainly in epilepsy.

SourceMemorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine

iron supplementsMinor

Flaxseed phytates can modestly reduce non-heme iron absorption; separate iron supplements from large flax meals by 1–2 hours.

Food sources

Food	Amount	%DV
Flaxseed oil	1 tbsp (7.3 g ALA)	456%
Chia seeds	1 oz (5.1 g ALA)	319%
Walnuts	1 oz (2.6 g ALA)	163%
Flaxseed (ground)	1 tbsp (2.4 g ALA)	150%
Canola oil	1 tbsp (1.3 g ALA)	81%
Soybean oil	1 tbsp (0.9 g ALA)	56%
Edamame, cooked	1 cup (0.6 g ALA)	38%
Hemp seeds	3 tbsp (3.0 g ALA + 0.5 g GLA)	188%
Tofu, firm	100 g (0.3 g ALA)	19%

Flaxseed oil

Amount: 1 tbsp (7.3 g ALA)
%DV: 456%

Chia seeds

Amount: 1 oz (5.1 g ALA)
%DV: 319%

Walnuts

Amount: 1 oz (2.6 g ALA)
%DV: 163%

Flaxseed (ground)

Amount: 1 tbsp (2.4 g ALA)
%DV: 150%

Canola oil

Amount: 1 tbsp (1.3 g ALA)
%DV: 81%

Soybean oil

Amount: 1 tbsp (0.9 g ALA)
%DV: 56%

Edamame, cooked

Amount: 1 cup (0.6 g ALA)
%DV: 38%

Hemp seeds

Amount: 3 tbsp (3.0 g ALA + 0.5 g GLA)
%DV: 188%

Tofu, firm

Amount: 100 g (0.3 g ALA)
%DV: 19%

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

ALA from food (flaxseed, chia, walnuts, canola, hemp) — far preferred over capsules

If using flaxseed oil, refrigerate after opening (highly oxidation-prone) and check for a freshness date

GLA: borage oil with 'UPA-free' or 'PA-free' certification (<1 µg pyrrolizidine alkaloids/day)

Borage oil GLA content (20–25% per gram); evening primrose ~9% — calculate per-day GLA from the label

Third-party tested (USP, NSF, IFOS for fish oils) for rancidity, peroxide value, heavy metals

Soft-gel capsules with dark or opaque packaging to protect PUFAs from oxidation

Be skeptical of…

'Plant-based omega-3 replaces fish oil' — conversion to EPA/DHA is too inefficient; use algal oil if seafood is off the table

'Cures eczema' for evening primrose / borage — Cochrane 2013 found no clinically meaningful benefit

'Hormonal balance / PMS cure' — small effect at best; modern guidelines do not recommend EPO routinely for PMS

Borage oil products without UPA-free certification — hepatotoxic risk

Mega-dose flaxseed oil marketed for cancer prevention — high-dose ALA and prostate cancer signal is unresolved

'Anti-aging' or 'youth oil' marketing without specific clinical claims — pure puffery

Frequently asked questions

Are alpha-linolenic and gamma-linolenic the same?⌄

No. Despite similar names, ALA is omega-3 (from flax, chia, walnuts) and GLA is omega-6 (from borage, evening primrose). They have different metabolic roles.

Can I rely on ALA instead of fish oil?⌄

Only partially. Most people convert only 5-15% of ALA to EPA and less than 1% to DHA. If you want robust omega-3 effects, EPA/DHA from fish oil or algae oil are more reliable.

Is GLA worth taking for joint pain?⌄

For rheumatoid arthritis, moderate evidence supports GLA at 1.4+ g/day. For general joint pain, evidence is weaker; other interventions may be more effective.

How much ALA do I need?⌄

Adequate Intake is 1.1 g/day for women and 1.6 g/day for men. One tablespoon of ground flaxseed provides roughly 2.4 g.

References by claim

ALA for cardiovascular disease prevention

Pan et al., 2012 — American Journal of Clinical Nutrition (2012) link

NIH Office of Dietary Supplements — Omega-3 Fatty Acids — Health Professional Fact Sheet (2024) link

GLA for rheumatoid arthritis pain

Cameron, Gagnier, Chrubasik 2011 — Cochrane Database of Systematic Reviews (2011) link

Memorial Sloan Kettering — About Herbs: Borage — MSKCC Integrative Medicine (2024) link

GLA for atopic eczema / dermatitis

Bamford et al., 2013 — Cochrane Database of Systematic Reviews — atopic eczema (2013) link

Other references

Linolenic Acids on NIH DSLD — NIH Dietary Supplement Label Database link

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Evidence-based·Last reviewed May 31, 2026·Evidence current as of May 31, 2026·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.