GLA, Inflammation & Skin: How FADS Genes and Diet Interact

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on diet & genetics. Browse all Diet & Genetics education

Gamma-linolenic acid, or GLA, is an omega-6 fatty acid found in evening primrose, borage, and blackcurrant seed oils. It sits at an unusual crossroads: while most omega-6 fats are associated with inflammation, GLA is converted in the body into anti-inflammatory signaling molecules. Whether you get that benefit depends heavily on your genetics and your diet.

How GLA works in the body

Your body normally makes small amounts of GLA from linoleic acid, the most common omega-6 fat in the modern diet. From GLA, cells produce dihomo-gamma-linolenic acid (DGLA), which feeds into anti-inflammatory prostaglandins (notably PGE1) rather than the pro-inflammatory cascade. That conversion is why GLA-rich oils have been studied for skin barrier support, eczema-related dryness, and inflammatory comfort.

The catch: the enzymes that run this pathway are rate-limiting. If they work slowly, dietary linoleic acid does not efficiently become GLA and DGLA — and supplementing GLA directly can matter more for some people than others.

The genes that set your conversion rate

Two neighboring genes, FADS1 and FADS2, encode the fatty-acid desaturase enzymes (delta-5 and delta-6 desaturase) that control this pathway. A widely studied variant, rs174537 near FADS1, is strongly associated with how efficiently people convert precursor fats into downstream fatty acids like GLA, DGLA, and arachidonic acid.

People with "slow-converter" versions of FADS genes produce less GLA from dietary linoleic acid. Interestingly, the frequency of fast- versus slow-converting variants differs sharply across ancestral populations, reflecting historical diets. This is one of the clearest examples of gene–diet interaction in human nutrition — the same food can have different downstream effects depending on your FADS genotype.

GLA, inflammation, and the skin barrier

The skin relies on fatty acids to build a healthy barrier that holds in moisture and calms irritation. Because GLA and DGLA feed anti-inflammatory signaling, researchers have examined GLA-rich oils in the context of dry, itchy, eczema-prone skin and general skin-barrier support. Results are mixed across studies, and effects tend to be modest and individual.

Part of that inconsistency likely traces back to FADS genetics: a trial that mixes fast and slow converters together can blur a real effect that exists only in the people whose enzymes limit their own GLA production. This is educational context, not a treatment claim — GLA is not a cure for any skin condition.

Diet is half the equation

Genetics sets your conversion efficiency, but diet sets the raw material and the balance. A diet heavy in linoleic acid but low in preformed GLA and omega-3s can tilt signaling toward inflammation, especially in slow converters. Whole-food sources of omega-3s, adequate micronutrients (zinc, magnesium, B vitamins act as enzyme cofactors), and GLA-containing oils all feed the same machinery.

The practical point is that "eat more healthy fats" is too generic. Your FADS genotype helps explain why a given fat strategy works well for one person and does little for another — insight you can bring to a provider or dietitian.

What your genetic results reveal

The Precision Peptide Genetic Test analyzes your biology across 14 pathways, 49 peptides, 150+ genetic insights, including fatty-acid metabolism pathways shaped by FADS1 and FADS2. Seeing your conversion profile reframes GLA from a generic supplement into a personalized question: are you likely a slow converter who benefits more from preformed GLA and omega-3s, or a fast converter who makes plenty on your own?

That is direction, not a prescription. PlexusDx tells you about your biology; it does not tell you what to put in your body. Decisions about supplements and skin care belong with you and a qualified provider.

Frequently Asked Questions About GLA, Genetics, and Skin

Which genes affect how I use GLA?

The FADS1 and FADS2 genes encode desaturase enzymes that convert dietary omega-6 fats into GLA and its anti-inflammatory downstream product DGLA. Variants such as rs174537 are strongly associated with conversion efficiency, so your FADS genotype helps explain how much benefit you get from GLA-rich foods or oils.

Why is GLA different from other omega-6 fats?

Most dietary omega-6 feeds pro-inflammatory signaling, but GLA is converted to DGLA, which supports anti-inflammatory prostaglandins like PGE1. This is why GLA-rich oils such as evening primrose and borage are studied for skin-barrier and inflammatory comfort, even though they are technically omega-6 fatty acids.

Can GLA supplements clear up eczema or skin conditions?

No. Research on GLA-rich oils for eczema-related dryness and skin-barrier support is mixed, and GLA is not a treatment or cure for any skin condition. Individual response varies, partly due to FADS genetics. Discuss any skin concern and supplement use with a qualified healthcare provider.

Does diet change how GLA works for me?

Yes. Genetics sets your conversion efficiency, but diet supplies the raw materials. A balance of omega-3s, preformed GLA sources, and enzyme cofactors like zinc and magnesium all influence the pathway. Your FADS genotype and your diet together shape how GLA affects inflammation and skin.

Wondering whether you convert omega-6 fats efficiently? Take the Precision Peptide Genetic Test to see how your own genetics shape these pathways — clarity you can bring to your next conversation with a qualified provider.

This article is part of the PlexusDx Education Hub. Browse all Diet & Genetics education

Disclaimer: The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use, and it does not diagnose, treat, cure, or prevent any condition. Consult a qualified healthcare provider before beginning any peptide protocol.