PEH balance in hair care: how to combine proteins, emollients, and humectants?

Conscious hair care is based on the understanding that the hair shaft is not a living structure but a dead keratin fiber incapable of self-regeneration. Consequently, it is crucial to supply the hair from the outside with appropriate building blocks, moisturizing agents, and protective substances. In trichology, a fundamental principle is maintaining the so-called PEH balance—the proper ratio of proteins, emollients, and humectants. A lack of this harmony quickly leads to dryness, roughness, a loss of elasticity, or the hair becoming excessively weighed down.

Hair porosity as a starting point for hair care

Before reaching for advanced products, a patient must determine the degree to which their hair cuticles are raised—in other words, their hair porosity. This factor dictates how the hair shaft absorbs specific nutrients. Low-porosity hair features tightly adhering cuticles; while smooth, it struggles to absorb moisture and is easily weighed down. Medium-porosity hair has slightly raised cuticles and represents an intermediate state, making it prone to frizz in humid conditions. In contrast, high-porosity hair has a structure with widely raised cuticles; this facilitates the absorption of substances but causes rapid moisture loss and makes the hair highly susceptible to mechanical damage.

PEH balance – what are proteins, emollients, and humectants?

Managing the condition of your hair requires a precise balance of three groups of active ingredients: emollients, humectants, and proteins. Each plays a distinct biological and physicochemical role on the hair shaft. Many people wonder what exactly these emollients, humectants, and proteins are, and how to manage them when dealing with dry hair. The key is understanding that these three pillars must complement one another; improper rotation can quickly lead to a deterioration in hair health. You can find a comprehensive discussion of this topic, along with detailed information on ingredient nomenclature, in our dedicated article:

The role of emollients in protection and smoothing

When considering what hair emollients are, it is worth noting that they comprise a broad group of lubricating substances, including plant oils, cosmetic butters, waxes, and silicones. Their primary function is to coat the hair shaft with an occlusive layer that prevents moisture loss and protects against the harmful effects of external factors. When looking for the best examples of hair emollients to incorporate into a daily routine, it is advisable to opt for natural oils and household emollients—such as olive oil or coconut oil—used in moderation.

The choice of emollients must absolutely take porosity into account. Oils with small molecules work well for low-porosity hair, whereas polyunsaturated oils with large molecules (such as grapeseed or hemp oil) are more effective for high-porosity hair, as they successfully seal gaps in the hair cortex.

Humectants as moisture regulators

Understanding what hair humectants are is essential for maintaining proper moisture balance. Humectants are hygroscopic compounds with a strong ability to bind and retain water molecules. This group includes, among others, hyaluronic acid, urea, glycerin, aloe vera, and panthenol. A look at common examples reveals that many of these humectants can be found in the kitchen pantry—such as honey or flaxseed gel.

However, it is important to keep in mind the specific nature of how they work: when used in their pure form under extreme weather conditions, humectants can produce the opposite of the intended effect. In conditions of extreme humidity or dryness, an excess of humectants risks causing sudden frizz and a loss of control over the hairstyle. For this reason, humectants must always be sealed in with emollients.

Proteins – biological structural cement

Proteins are molecules of varying molecular weights (e.g., keratin, silk, collagen, hydrolyzed wheat or soy proteins) that penetrate damaged areas of the hair shaft and fill in gaps in the keratin structure. They act like a form of mortar, repairing micro-damage caused by hair treatments or heat styling.

If a patient has a protein deficiency, the hair becomes limp, loses volume, and stretches like rubber. Conversely, an excess of protein causes stiffness. It is therefore worth regularly assessing the condition of the hair to know when it needs protein and when it requires a dose of moisture.

Correct order and rules for using PEH

One of the most common questions patients ask concerns the nature of emollients, humectants, and proteins, and how to use these ingredients in practice. The correct order of application—proteins, humectants, and emollients—is fundamental to the final visual result.

Many people also wonder whether emollients or humectants should be applied to the hair first. The standard rule of conscious hair care dictates providing hydration (humectants) and—if needed—restoration (proteins), followed by sealing everything with an occlusive layer (emollients). To accurately determine whether your hair needs protein or hydration, it is worth performing a simple elasticity test or observing how the hair feels to the touch after washing.

Laboratory diagnostics for chronic hair thinning

If, despite a perfectly balanced hair care routine based on PEH principles, hair continues to fall out, lose its shine, or undergo miniaturization, the problem lies deeper than the surface structure of the hair shaft itself. In such cases, a thorough systemic diagnosis is necessary.

As part of the trichological assessment, it is recommended to undergo basic blood tests:

• peripheral blood count, ruling out anemic conditions,
• serum ferritin and iron concentrations (responsible for the oxygenation of the matrix),
• assessment of vitamin D3 levels and thyroid profile (TSH, fT3, fT4).

Professional in-office treatments to support hair health

When home remedies and a strategic rotation of hair care products fail to yield the expected improvements in density and structure, advanced aesthetic medicine and clinical trichology offer a solution. Treatments that stimulate microcirculation nourish dormant hair follicles from within.

The most effective in-office methods include:

• Biostimulation with platelet-rich plasma (PRP) – the use of autologous growth factors from the patient’s blood for deep tissue regeneration.
• Scalp needle mesotherapy – delivery of vitamins, amino acids, and nutrients directly into the dermis.