Search Skin Biology

Hydrogels for Osteochondral
Tissue Engineering
Journal of Biomedical

(March 2020)
Anti-Wrinkle Activity
& Transdermal Delivery
of GHK Peptide
Journal of Peptide Science
(March 2020)
Pulsed Glow Discharge
to GHK-Cu Determination
International Journal
of Mass Spectrometry

(March 2020)
Protective Effects of GHK-Cu
in Pulmonary Fibrosis
Life Sciences
(January 2020)
Anti-Wrinkle Benefits
of GHK-Cu Stimulating
Skin Basement Membrane
International Journal of Molecular Sciences
(January 2020)
Structural Analysis
Molecular Dynamics of
Skin Protective
TriPeptide GHK
Journal of Molecular Structure
(January 2020)
In Vitro / In Vivo Studies
pH-sensitive GHK-Cu in
Superabsorbent Polymer
GHK Enhances
Stem Cells Osteogenesis
Acta Biomaterialia
Antibacterial GHK-Cu
Nanoparticles for
Wound Healing
Particle & Particle (2019)
Effect of GHK-Cu
on Stem Cells and
Relevant Genes
OBM Geriatrics
GHK Alleviates
Neuronal Apoptosis Due
to Brain Hemorrhage
Frontiers in Neuroscience
Endogenous Antioxidant
International Journal of Pathophysiology and Pharmacology (2018)
Regenerative and
Protective Actions of
GHK-Cu Peptide
International Journal of
Molecular Sciences
Skin Regenerative and
Anti-Cancer Actions
of Copper Peptides
GHK-Cu Accelerates
Scald Wound Healing
Promoting Angiogenesis
Wound Repair and

GHK Peptide Inhibits
Pulmonary Fibrosis
by Suppressing TGF-β1
Frontiers in Pharmacology
Skin Cancer Therapy
with Copper Peptides
The Effect of Human
Peptide GHK Relevant to
Nervous System Function
and Cognitive Decline
Brain Sciences (2017)
Effects of Tripeptide
GHK in Pain-Induced
Aggressive Behavior
Bulletin of Experimental
Biology & Medicine
GHK-Cu Elicits
In Vitro Alterations
in Extracellular Matrix
Am Journal of Respiratory
and Critical Care Medicine

Selected Biomarkers &
Copper Compounds
Scientific Reports

GHK-Cu on Collagen,
Elastin, and Facial Wrinkles
Journal of Aging Science
Tri-Peptide GHK-Cu
and Acute Lung Injury

Effect of GHK Peptide
on Pain Sensitivity
Experimental Pharmacology

New Data of the
Cosmeceutical and
TriPeptide GHK
SOFW Journal
GHK Peptide as a
Natural Modulator of
Multiple Cellular Pathways
in Skin Regeneration
BioMed Research (2015)
Resetting Skin Genome
Back to Health
Naturally with GHK
Textbook of Aging Skin
GHK-Cu May Prevent
Oxidative Stress in Skin
by Regulating Copper and
Modifying Expression of
Numerous Antioxidant Genes Cosmetics (2015)
GHK Increases
TGF-β1 in
Human Fibroblasts

Acta Poloniae

The Human Skin Remodeling Peptide Induces Anti-Cancer
Expression and DNA Repair Analytical Oncology
Resetting the
Human Genome to Health
BioMed Research
Enhanced Tropic Factor Secretion of Mesenchymal
Stem Cells with GHK
Acta Biomater
Anxiolytic (Anti-Anxiety)
Effects of GHK Peptide
Bulletin of Experimental
Biology & Medicine
Lung Destruction and
its Reversal by GHK
Genome Medicine
TriPeptide GHK Induces
Programmed Cell Death
of Neuroblastoma
Journal of Biotechnology
Stem Cell
Recovering Effect
of GHK in Skin
Peptide Science
Skin Penetration of
Copper Tripeptide in Vitro
Journal of International
Inflammation Research
Possible Therapeutics
for Colorectal Cancer
Journal of Clinical and
Experimental Metastasis
Methods of Controlling
Differentiation and
Proliferation of Stem Cells
Effects of
Copper Tripeptide
on Irradiated Fibroblasts
American Medical Association
Avoid Buying Fake Copper Peptides Dangerous

What is SPF?

The ability of a sunscreen to protect the user from UVB rays is defined as its Sun Protection Factor (SPF). The SPF is the ratio of the amount of ultraviolet radiation required to produce minimal pinkness (erythema) in skin covered by a sunscreen, assessed 24 hours after exposure, to the amount of UV radiation required to produce a similar level of pinkness in unprotected skin. If a sunscreen reduces the effect of sunlight on skin by 50% it would have an SPF of 2, if by 75%, the SPF would be 4, and so on. Most sunscreens have SPF ratings from four to as high as 40 or 50. The level of protection from ultraviolet radiation provided by the product increases as the value of the SPF rating increases.

The SPF applies for UVB rays only. The protection provided against UVA rays in chemical sunscreens is about 10% of the UVB rating.

An SPF of 15 will provide 15 times the amount of protection you'd get without using anything. Thus, if 10 minutes in the sun is enough to turn you red, your sunscreen would allow you to stay out for 150 minutes before burning. An SPF of 15 filters approximately 92% of the sun burning rays. For UVA the degree of protection is defined as the Phototoxic Protective Factor (PPF). These values are much lower, ranging from 1.5 - 4.8, because the energy contained in UVA is so much less.

Sunscreen Typeslounging woman in the sun

Sunscreens are designed to protect against sunburn (UVB rays) and generally provide little protection against UVA rays. They come in two forms:

CHEMICAL SUNSCREENS prevent sunburn by absorbing the ultraviolet (UVB) rays but may increase your risk of cancers of the breast, ovaries, prostate, and colon. Chemicals such as avobenzone, benzophenone, ethylhexyl p-methoxycinnimate, 2-ethylhexyl salicylate, homosalate, octyl methoxycinnamate, oxybenzone (benzophenone-3) are used as the active ingredients.

PHYSICAL SUNSCREENS contain inert minerals such as titanium dioxide, zinc oxide, or talc and work by reflecting the ultraviolet (UVA and UVB) and visible rays away from the skin.

Questions or Advice?

Email Dr. Loren Pickart at

Call us at 1-800-405-1912 Monday Through Friday (8 am to 6 pm) PST

Sunscreen Typeswoman in the sun


Use Non-Encapsulated Reflective Physical Sunscreens

Physical reflective sunblockers contain inert minerals such as titanium dioxide, zinc oxide, red petrolatum, or talc and work by reflecting the ultraviolet (UVA and UVB) rays away from the skin. They come in two forms - pure sunblocker and various micronized or encapsulated versions.

The best overall reflective sunblocker, at least in theory, is pure titanium dioxide. Zinc oxide has somewhat better UVA and UVB blocking but also can generate free ionic zinc ions on the skin. Some women think zinc oxide increases facial pore size. Since copper complexes are used by the body for skin regeneration and remodeling, the generation of zinc ions could displace copper ions and reduce the rate of skin renewal.

One problem with titanium dioxide is that it is whiter than zinc oxide and more difficult to formulate as a transparent products. Thus you may prefer zinc oxide products. Pure sunblockers tend to give a pasty look to the skin. This is the reason for the popularity of micronized sunblockers which give a better cosmetic appearance on the skin.

Avoid Micronized or Siliconized Physical Sunscreens.

Prof. Nicholas Lowe (Dermatology, UCLA) has reported that micronized or encapsulated physical sunblockers such as titanium dioxide penetrate into the skin while pure titanium dioxide remains on the skin's surface - where you really want it to stay.

Micronized minerals are usually used as 'micronized' particles in the size range of 20-50 microns. But these particles are small in comparison with the wavelength of the ultraviolet and visible light and are virtually invisible and do not effectively scatter of reflect light. Pure, non-micronized, and often pasty, minerals are better reflectors of ultraviolet light.

Not Recommended

Free Radical Generators and Estrogenic Chemicals

Chemical sunscreens act by strongly absorbing ultraviolet light in the UVB range (290 to 320 nm). They cannot reflect light. The UVB range is the range that is primarily responsible for sunburning and causing skin cancer. The UVA range (320 to 400 nm) is responsible for suntanning and photosensitivity reactions (increased sensitivity to sunlight as the result of certain medications, cosmetics, soaps, or plants). UVA is also responsible for serious skin damage. Such types of chemical sunscreens are potent generators of free radicals and many have strong estrogenic, "gender bending", activities and may increase your cancer risk for cancers of the breast, ovaries, prostate, and colon (see more below). PABA and PABA esters are rarely used today because of allergic problems.

Chemical Sunscreens Include:

Benzophenones (dixoybenzone, oxybenzone)

PABA and PABA esters (ethyl dihydroxy propyl PAB, glyceryl PABA, p-aminobenzoic acid, padimate-O or octyl dimethyl PABA)

Cinnamates (cinoxate, ethylhexyl p-methoxycinnamate, octocrylene, octyl methoxycinnamate)

Salicylates (ethylhexyl salicylate, homosalate, octyl salicylate)

Digalloyl trioleate

Menthyl anthranilate

Avobenzone [butyl-methyoxydibenzoylmethane; Parsol 1789] - This is the only chemical sunscreen currently allowed by the European Community. However, its safety is still questionable since it easily penetrate the skin and is a strong free radical generator.

Effectiveness and Safety of Various Sunscreens and Sunblockers

Sunblocker or Sunscreen Sunscreen chemicals
UV protective properties Good but partial spectrum
UV blocking properties Absorbs photons
Free radical generating ability High
Ability to penetrate skin barrier High
Relative danger High


Sunblocker or Sunscreen Titanium Dioxide
UV protective properties Very broad spectrum
UV blocking properties Mainly reflects and scatters photons, some photon absorption
Free radical generating ability Low
Ability to penetrate skin barrier Virtually none
Relative danger Very low - the safest known


Sunblocker or Sunscreen Zinc Oxide
UV protective properties Broadest spectrum
UV blocking properties Mainly reflects and scatters photons, some photon absorption
Free radical generating ability Low
Ability to penetrate skin barrier Virtually none
Relative danger May generate zinc ions that decrease skin repair


Sunblocker or Sunscreen Micronized or siliconized titanium dioxide or zinc oxide
UV protective properties Broad spectrum
UV blocking properties Mainly reflects and scatters photons, some photon absorption
Free radical generating ability Low
Ability to penetrate skin barrier Low but significant
Relative danger Moderate

Do Physical Sunblockers Generate Free-Radicals?woman naked in the sun

There have been reports that physical sunblockers can also generate free radicals after exposure to ultraviolet light. However, even bare skin will generate free radicals when exposed to UV radiation. The key is whether the sunblocker form will penetrate the skin and be near the skin's sensitive proteins and DNA. Pure sunblockers such as zinc oxide and titanium dioxide do not pass into the skin and remain far from the skin's sensitive areas. However, sunblockers that are micronized and coated with plastics or silicone more easily pass the skin barrier and can reach the skin's sensitive areas. For this reason, pure physical sunblockers are the safest.

Do Chemical Sunscreens in Cosmetics Increase Cancer?

Worldwide, the greatest rise in melanoma has been experienced in countries where chemical sunscreens have been heavily promoted. The rise in melanoma has been exceptionally high in Queensland, Australia where the medical establishment has vigorously promoted the use of sunscreens. Queensland now has more incidences of melanoma per capita than any other place.

Drs. Cedric and Frank Garland of the University of California have pointed out that while sunscreens do protect against sunburn, there is no scientific proof that they protect against melanoma or basal cell carcinoma in humans1. The Garlands believe that the increased use of chemical sunscreens is the primary cause of the skin cancer epidemic. There is, however, some evidence that regular use of sunscreens helps prevent the formation of actinic keratoses, the precursors of squamous cell carcinoma.