Lab Notes

What makes an ingredient science-based?

How do you know if an ingredient is Science-based? How many journals should one read to say you know an ingredient? How do you assess the studies after reading them?

How do we assess ingredients?

Assessing ingredients is probably one of of our activities that a lot of us look forward to. It is quite a rigorous task but we love how in depth it can get as the devil is always in the details. 

I admit we're pretty slow in releasing in-depth Encyclopedia Entries on a particular ingredient, but it's only because each of those take minimum two weeks to complete. We want to scour everything that is out there and fully assess and understand how an ingredient work. However, how exactly do we assess them? 

As science people, we love to make order out of chaos. Guides, charts, standards are kinda our thing, so it's not surprising that we also have a Guideline when assessing ingredients

The Kligman Standard and the Regimenlab Evidence Grading

The Kligman Standard and the Regimen Evidence Grading are the standards that we use to evaluate and grade every active ingredient that goes into Regimen skincare. They are a set of questions we ask to determine if an ingredient is science based. Albert Kligman was a pioneer of modern skincare. He was an American dermatologist who co-invented Retin-A and developed this BS detector called The Kligman Standard. 

Each ingredient entry in our Skincare Encyclopedia has a TMI section, which will give you its rating against the Kligman Standard. Some might even say too much information. The Kligman Standard evaluates penetration and quality. We'll break it down for you. 

The Kligman Standard is composed of three criteria:

  • Does it penetrate the skin?
  • Does it have a well-established biochemical mechanism of action?
  • Does it have a sufficient level of evidence?

We've slightly modified these three to have a more detailed and rigorous analysis of active ingredients. Let's discuss each of them.


This scores how readily an ingredient penetrates the skin. Penetration is a key criterion as many of the skin's biochemical processes happen in the nucleated cells (starting from the Stratum Granulosum (SG) to the Dermis). Cells above the SG are considered physiologically dead so actives cannot upregulate nor inhibit any genes. 

There are a lot of unique phytochemicals that have great in-vitro results but have poor penetration. Unfortunately, unless some of it penetrates, they can't do what they are supposed to be doing. 

On the other hand, not all actives need to penetrate the skin. Some are happy to work just on the surface, while some prefer to work just at the border. When we analyze the penetration of actives on our Ingredient Encyclopedia, we will tackle the theoretical penetration the active needs and the proven penetration of the active. 


Biochemical Mechanism of Action

The question "How" is probably our favourite question. This is the part we are proud to show off. We like to obsess about the biochemical Mechanism of Action to figure out if there is a way for a particular active to do what it is supposed to do. We can't just take the word of suppliers that Guava Extract is a good antioxidant. We need to figure out which particular compound/compounds are responsible for the effect. How do they affect the biochemistry of the cell? Can we use the pure compound instead?

Level of Evidence

In the original criteria for the Kligman Standard, the level of evidence required is unclear. Since it only asked if there was enough evidence, but didn’t define what was enough, we decided to make our own standard that was less subjective as it is hard to say when an evidence is enough.

The Regimen Evidence Grading is based on Source 1 and Source 2.  The first section is a letter grading corresponding to the level of studies done on the active. We gather as many studies as we can and grade the collection against an A, B or C standard. 


Level A
Experimental study, randomized controlled trial (RCT) Systematic review of RCTs including in-vitro investigation of biochemical mechanism, with or without meta-analysis.

Level B
A well-designed, nonrandomized, clinical trial, clinical cohort studies, lower quality randomized controlled trials, with or without meta-analysis and case-controlled studies with unbiased selection of study participants and consistent findings. A non quantitative systematic review with appropriate search strategies and well-substantiated conclusions.

Level C
Emerging Research. Proof of concept studies with or without control with small number of test subjects. Opinion of respected authorities and/or nationally recognized expert committees/consensus panels based on scientific evidence

The second section evaluates the studies completed. Here's how we determine the quality of this research.  

High quality
Consistent, generalizable results; sufficient sample size for the study design; adequate control; definitive conclusions; consistent recommendations based on comprehensive literature review that includes thorough reference to scientific evidence; Material officially sponsored by a professional, public, private organization, or government agency; documentation of a systematic literature search strategy; criteria-based evaluation of overall scientific strength and quality of included studies and definitive conclusions; national expertise is clearly evident; developed or revised within the last 5 years.

Good quality
Reasonably consistent results; sufficient sample size for the study design; some control, fairly definitive conclusions; reasonably consistent recommendations based on fairly comprehensive literature review that includes some reference to scientific evidence; Material officially sponsored by a professional, public, private organization, or government agency; reasonably thorough and appropriate systematic literature search strategy; evaluation of strengths and limitations of included studies with fairly definitive conclusions; national expertise is clearly evident; developed or revised within the last 5 years.

Low quality
Little evidence with inconsistent results; insufficient sample size for the study design; conclusions cannot be drawn; Material not sponsored by an official organization or agency; undefined, poorly defined, or limited literature search strategy; no evaluation of strengths and limitations of included studies, insufficient evidence with inconsistent results, conclusions cannot be drawn; not revised within the last 5 years.

For each ingredient that we analyze in our Skincare Encyclopedia, we add a grade for it. You now know what those "Level B: Good Quality Evidence" mean. You can even apply this Guide to reading journals outside of skincare.