diff --git a/include/openssl/evp.h b/include/openssl/evp.h
index 58b388aa5..e8deb109e 100644
--- a/include/openssl/evp.h
+++ b/include/openssl/evp.h
@@ -577,7 +577,10 @@ OPENSSL_EXPORT int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx,
 /* EVP_PKEY_CTX_set_rsa_pss_saltlen sets the length of the salt in a PSS-padded
  * signature. A value of -1 cause the salt to be the same length as the digest
  * in the signature. A value of -2 causes the salt to be the maximum length
- * that will fit. Otherwise the value gives the size of the salt in bytes.
+ * that will fit when signing and recovered from the signature when verifying.
+ * Otherwise the value gives the size of the salt in bytes.
+ *
+ * If unsure, use -1.
  *
  * Returns one on success or zero on error. */
 OPENSSL_EXPORT int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx,
diff --git a/include/openssl/rsa.h b/include/openssl/rsa.h
index 78d5b32c6..19be3ba5d 100644
--- a/include/openssl/rsa.h
+++ b/include/openssl/rsa.h
@@ -322,7 +322,9 @@ OPENSSL_EXPORT int RSA_recover_crt_params(RSA *rsa);
  * hash function for generating the mask. If NULL, |Hash| is used. The |sLen|
  * argument specifies the expected salt length in bytes. If |sLen| is -1 then
  * the salt length is the same as the hash length. If -2, then the salt length
- * is maximal and is taken from the size of |EM|.
+ * is recovered and all values accepted.
+ *
+ * If unsure, use -1.
  *
  * It returns one on success or zero on error. */
 OPENSSL_EXPORT int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const uint8_t *mHash,