Glycolic Acid

Introduction

What is glycolic acid?

Glycolic acid is a natural α-hydroxy acid found in many plants, especially sugar cane (R), but most glycolic acid in use today is synthesised chemically.

Does glycolic acid get absorbed?

Glycolic acid has the smallest molecular weight amongst all of the α-hydroxy acids, and therefore penetrates the skin easily (R). 24 hours after 4% glycolic acid was applied to human skin sections, 2.7% of the applied dose was found in the stratum corneum and 13.5% in the viable skin (R).

In general, gel formulations of glycolic acid penetrate more slowly (R). Absorption is also pH, strength and time-dependent. Decreasing the skin's pH increases its permeability to glycolic acid (R), while the depth of penetration relies on the duration over which glycolic acid was applied (R).

Efficacy

Show 10 more outcomes
Outcome	Grade	Effect	Evidence	Studies
Skin Smoothness	B	🠩 Slight	★★★ Fair	3 studies 169 participants
Skin Brightness	B	🠩 Slight	★★★ Fair	3 studies 111 participants
Skin Firmness	B	🠩 Slight	★★★ Fair	3 studies 106 participants
Sunburn	C	🠩 Slight	★★ Some	1 study 10 participants
Skin Thickness	C	⇧ Potential	★★★ Fair	5 studies 42 participants
Wrinkles	C	⇩ Potential	★★★ Fair	4 studies 178 participants
Hyperpigmentation	C	⇩ Potential	★★★ Fair	4 studies 177 participants
Skin Barrier Function	C	⇩ Potential	★★★ Fair	3 studies 63 participants
Skin Hydration	C	⇧ Potential	★★★ Fair	3 studies 52 participants
Fine Lines	C	⇩ Potential	★★ Some	2 studies 100 participants
Hypopigmentation	C	⇩ Potential	★★★ Fair	1 study 69 participants
Facial Pores	C	⇩ Potential	★★ Some	1 study 57 participants
Actininc Keratoses	E	– No Effect	★★★ Fair	1 study 69 participants
Skin Redness	E	– No Effect	★★★★ Good	1 study 52 participants
Skin pH	E	– No Effect	★★★★ Good	1 study 52 participants

Mechanisms

Show 6 more outcomes
Outcome	Grade	Effect	Evidence	Studies
Rete Pegs	A	🠩🠩🠩 Marked	★★★★ Good	1 study 15 participants
Elastic Fibres	C	⇧ Potential	★★★ Fair	3 studies 28 participants
Glycosaminoglycans	C	⇧ Potential	★★ Some	2 studies 13 participants
Skin Cell Renewal	C	⇧ Potential	★★ Some	1 study 8 participants
Blood Vessels	E	– No Effect	★★★ Fair	2 studies 23 participants
Collagen	E	– No Effect	★★★ Fair	2 studies 20 participants
Proteoglycans	E	– No Effect	★★★ Fair	1 study 8 participants
Filaggrin	E	– No Effect	★★★ Fair	1 study 8 participants
Transglutaminase	E	– No Effect	★★★ Fair	1 study 8 participants
Keratinocyte Proliferation	E	– No Effect	★★★ Fair	1 study 8 participants
Inflammation	E	– No Effect	★★ Some	1 study

Side Effects

Outcome	Effect	Frequency	Studies
Skin Sensitivity	⇧ Increase	13% (2 out of 15 participants)	1 study
Irritation	⇧ Increase	13% (1 out of 8 participants)	1 study
Skin Redness	⇧ Increase	—	3 studies

Latest Research

What is glycolic acid?

Does glycolic acid get absorbed?

A novel, volumizing cosmetic formulation significantly improves the appearance of target Glabellar lines, nasolabial folds, and crow's feet in a double-blind, vehicle-controlled clinical trial (2014)

A double-blind, randomized clinical trial of 20% alpha/poly hydroxy acid cream to reduce scaling of lesions associated with moderate, chronic plaque psoriasis (2013)

Analytic assessment under ultraviolet light of actinic lentigines under bleaching treatment (2011)

Evaluation of a kojic acid, emblica extract, and glycolic acid formulation compared with hydroquinone 4% for skin lightening (2010)

Lactobionic acid in a natural alkylpolyglucoside-based vehicle: assessing safety and efficacy aspects in comparison to glycolic acid (2010)