Glyoxylic Acid and Hair Straightening: Dangers, ANSES Warning, and Safe Alternatives

Glyoxylic Acid and Hair Straightening: Dangers, ANSES Alert, and Safe Alternatives

By Paris Liss — Experts in professional hair straightening for 25 years

Since October 2024, glyoxylic acid has been at the heart of a major health controversy in the world of hair straightening. ANSES (French Agency for Food, Environmental and Occupational Health & Safety) issued an official alert after several cases of acute kidney failure linked to the use of straightening products containing this substance. As experts in professional straightening for 25 years, we have a duty to inform you clearly on this subject — and to guide you towards safe and effective alternatives.

What is glyoxylic acid?

Glyoxylic acid is an organic chemical acid introduced into hair straightening products as an alternative to formaldehyde, which is prohibited due to its very high toxicity. For several years, it has been presented as a safer solution — capable of effectively straightening hair without the risks associated with formaldehyde.

Its mechanism is simple: it temporarily alters the structure of the hair fiber under the effect of heat from a straightening iron, allowing for a long-lasting straightening result. It is present in many Brazilian straighteners sold on the market under various names.

The ANSES alert of October 2024 — What you need to know

On October 16, 2024, ANSES, the DGCCRF (Directorate General for Competition, Consumer Affairs and Fraud Control) and the Directorate General for Health jointly published an official statement alerting hairdressing professionals and individuals to the potential dangers of straightening products containing glyoxylic acid.

The alarming figures:

• 26 cases of acute kidney failure reported in 2023 among women who used glyoxylic acid straighteners
• 4 new cases reported since early 2024 in France
• The actual number of cases is likely underestimated due to lack of awareness of the phenomenon

What happens in the body: Glyoxylic acid, upon penetrating the blood via the scalp during application, causes the formation of calcium oxalate crystals in the kidneys. These crystals obstruct kidney function and can lead to acute kidney failure — a serious medical emergency.

Symptoms to watch for:

• Abdominal or lower back pain
• Nausea and/or vomiting
• Onset of symptoms a few hours after application

⚠️ If you or your client experience these symptoms after a straightening treatment, consult a doctor immediately or call a poison control center, specifying that you have been in contact with a straightening product.

Poison control center numbers in France

Paris: 01 40 05 48 48
Lyon: 04 72 11 69 11
Marseille: 04 91 75 25 25
Bordeaux: 05 56 96 40 80
Lille: 08 00 59 59 59
Nancy: 03 83 22 50 50
Angers: 02 41 48 21 21
Toulouse: 05 61 77 74 47

How to identify glyoxylic acid in a straightening product

Many manufacturers do not clearly mention this ingredient on their labels. Here's how to spot it in the INCI list (official ingredient list):

• Glyoxylic Acid → this is glyoxylic acid
• Acide glyoxylique → same thing in French

The important confusion: Glyoxylic acid ≠ Glyoxyloyl carbocysteine

This is the point that almost no one explains clearly — and yet it's crucial for making the right choice.

Glyoxyloyl carbocysteine is often confused with glyoxylic acid because its name is similar — but it is a much more stable and better-tolerated derivative, combined with keratin amino acids. It offers a gentler and hair-fiber-friendly straightening without the kidney risks associated with pure glyoxylic acid.

Our expert opinion at Paris Liss

At Paris Liss, after 25 years of experience in professional straightening and rigorous testing of hundreds of products, we have always selected our products according to one non-negotiable criterion: safety first.

That's why we do not offer any products containing glyoxylic acid in our store. All our straightening treatments are formulated without formaldehyde, without glyoxylic acid, and comply with European standards — tested and validated by our expert Fatiha, a qualified hairdresser and trainer for over 25 years.

Safe and effective alternatives at Paris Liss

Good news: there are excellent, long-lasting straightening treatments without glyoxylic acid. Here are our recommendations based on your hair type:

For thick, resistant, Afro, or coily hair

Tahiti Gloss — Karité Straightening Our absolute bestseller. Without glyoxylic acid, without formaldehyde. Enriched with shea butter, Plex, Amla oil, and pure keratin — it straightens up to 100% even the most resistant hair while intensely nourishing it.

Lisa Indian — Deby Hair Indian Straightening The unique fusion of protein + tannin + Indian Amla oil. Without formaldehyde, without glyoxylic acid. Adjustable results from slightly straightening to 100% straightening depending on the protocol.

For fine, sensitized, or bleached hair

Excellence Straightening — Paris Liss Our signature product. 3-in-1 French + Indian + silk protein straightening. Formaldehyde-free, vegan, compliant with European standards. The first Paris Liss recommendation for fragile hair that classic straighteners cannot treat without risk.

Amla Plex Straightening — Elyssa Cosmétiques Formaldehyde-free Indian straightening based on Indian protein and Amla oil. Long-lasting results for 5 to 6 months. Formulated by a qualified pharmacist.

For colored or highlighted hair

Tannin Straightening — Salvatore Blue Gold Tannin is a 100% plant-based active ingredient, derived from plants. Without formaldehyde, without glyoxylic acid. It gently straightens, protects color, and nourishes the fiber — ideal after bleaching.

For a treatment between straightening sessions (non-straightening)

Glow Lift Hair Botox — Paris Liss Non-straightening treatment with pure keratin and diamond powder. Repairs, defines curls, and provides mirror-like shine. 100% formaldehyde-free and glyoxylic acid-free.

How to read a straightening product label — Practical guide

Before buying or using a straightening product, always check the INCI list:

✅ Safe ingredients to look for:

• Hydrolyzed Keratin
• Tannic Acid (vegetal tannin)
• Emblica Officinalis (Amla oil)
• Glyoxyloyl Keratin Amino Acids (mild derivative)
• Glycolic Acid (natural glycolic acid)

❌ Ingredients to avoid:

• Glyoxylic Acid
• Formaldehyde
• Methylene Glycol (formaldehyde releaser)
• Formalin

❓ FAQ — Frequently Asked Questions

Do all Brazilian straighteners contain glyoxylic acid? No. Many quality Brazilian straighteners are formulated without glyoxylic acid. You simply need to check the INCI list before purchasing. All Paris Liss straighteners are guaranteed glyoxylic acid-free.

Is glyoxylic acid banned in France? Not yet at the time of writing this article — but ANSES has launched an official investigation and called for urgent European regulation. As a precautionary measure, ANSES strongly advises against its use in straightening products.

Can I use my straightener if I don't know if it contains glyoxylic acid? If in doubt, do not use it. Contact the manufacturer or your supplier directly for the complete composition. At Paris Liss, we are available on WhatsApp every morning from Monday to Friday to answer your questions.

Are tannin straighteners really effective as an alternative? Yes — tannin straightening is one of the most effective and safest alternatives. Tannin is a natural plant-based active ingredient that smooths, tames, and coats the hair fiber in a long-lasting way, with no health risks.

What should I do if I have already used a glyoxylic acid straightener? If you have no symptoms, there's no immediate concern. Simply avoid reusing this type of product in the future. If you experience lower back or abdominal pain, or nausea in the hours following application — consult a doctor immediately, mentioning the product used.

Are Paris Liss straighteners compliant with European standards? Yes. All our products are tested, formaldehyde-free, glyoxylic acid-free, and compliant with European standards. This has been our commitment for 25 years.

In summary

Paris Liss — Experts in professional hair straightening and care for 25 years. All our products are selected according to strict criteria of safety, effectiveness, and compliance with European standards. Our expert is available on WhatsApp from Monday to Friday.