Most of the advertising for PE products market under a technique referred to as "implied fact". This is a common loop-hole and unfortunately legally a very difficult one to close.
Most of the advertising is very carefully reviewed by a legal department to not cross lines this leaves them an out should they be taken to court. Most of the makers of these products have been taken to court and multiple attempts have been made at shutting them down. Most of the makers of these same products have been sued for fraud and false advertising multiple times. They do not win on a basis of being able to prove that their products work they win on a legal technicality.
They never state who their medical experts and doctors are. Also they can legally state "Dr. Approved" if for example they hand their herbal concoction to an MD and the MD says. Yes, this will not kill you it is safe. The MD did not state it was effective and he did approve it for safety, but again not for effectiveness.
The implication is effectiveness the fact is safety.
A few years ago a famous maker of penis pumps had done what is called a "piggy back" approval under existing designs of his penis pump thinking he was going to outsmart the FDA. After he was approved for being a "clone" of other approved designs he began to market his device as a penis enlargement device that had FDA approval. Where they got him and finally I understand shut him down was that he claimed approval under a different usage and then had the stupidity to publically market in this vein.
The wording on this advertising is the secret. These manufacturers do have approval in that their combination of herbs and proprietary ingredients are all found in other supplements available much cheaper over the counter. As a result of this unless one is allergic to one or more of the ingredients it will get by.
This is twisted into "Doctor approved".
The companies are very careful not to state actual penis enlargment. Male enhancement is a very vague claim and it is hard to substantiate a claim against what constitutes "male enhancement". Similar to this are the words, "that special part of the male body". Again the wording is chosen very carefully to let you know exactly what they are talking about and yet not directly state penis enlargement as one of their facts.
None of this stuff works for penis enlargement and no where will they out and out state that this is the purpose of their supplement.
Here is the other blatant fact. Some years ago when Pro-hormones came to the market the drug laws had to be re-written. What they did was to base the final definition on cellular change. In order to have growth of a penis you would need cellular change. Any substance that can in fact cause cellular change is a drug and is not a supplement. There is some vagueness in this one as well, but, it gives great latitude to prosecuters.
This stuff is all totally bogus, there is currently no herbal preparation that has been biologically re-engineered to be active in humans. The minute it becomes and can be tested as biologically active it is no longer a supplement, but becomes a drug and that needs an Rx.
Under this standard the people at the various companies Extenze, Enzyte and all the rest have to prove that their compound is a supplement to market it, meaning that they have to prove it is not biologically active under health and safety codes THEN they have to turn around and market the stuff implying it is. .